balance = 1000
while True:
    print("\n=== ATM模拟系统 ===")
    print("1. 查询余额")
    print("2. 存款")
    print("3. 取款")
    print("4.退出")
    choice = input("请选则操作(1-4):")

    if choice =="1":
        print(f"当前余额: ￥{balance:.2f}")
    elif choice =="2":
        amount = float(input("输入存款金额:"))
        if amount >0:
            balance += amount
            print(f"存款成功!余额: ￥{balance:.2f}")
        else:
            print("金额必须大于0!")
    elif choice =="3":
        amount = float(input("输入存款余额:"))
        if amount > balance:
            print("余额不足!")
        if amount <= 0:
            print("金额无效!")
        else:
            balance -= amount
            print(f"存款成功!余额: ￥{balance:.2f}")
    elif choice =="4":
        print("感谢使用,再见!")
        break
    else:
        print("无效输入,请重新选择!")



while True:
    score = input("请输入成绩(0-100,输入q退出):")
    if score.lower() =='q':
       break

    try:
        score = float(score)
        if 0 <= score <= 100:
            if score >= 90:
                grade = "A"
            elif score >= 80:
                grade ="B"
            elif score >= 70:
                grade = "C"
            elif score >= 60:
                grade = "D"
            else:
                grade = "F"
            print(f"成绩等级:{grade}")
        else:
            print("成绩必须在0-100之间!")
    except ValueError:
        print("请输入数字!")



def is_prime(n):
    if n <= 1:
        return False
    for i in range(2, int(n**0.5)+1):
        if n % i ==0:
            return False
    return True




start = int(input("起始值"))
end = int(input("结束值:"))
print(f"{start}到{end}的素数")
for num in range(start, end+1):
    if is_prime(num):
        print(num, end=" ")

start = int(input("起始值: "))
end = int(input("结束值: "))
print(f"{start}到{end}的素数:")
for num in range(start, end+1):
    if is_prime(num):
        print(num, end=" ")

import random

words = ["python", "java", "javascript", "html", "css"]
secret_word = random.choice(words)
max_attempts = 5
hint = "_" * len(secret_word)

for attempt in range(1, max_attempts + 1):
    print(f"\n第{attempt}次尝试 | 当前提示: {hint}")
    guess = input("猜一个字母: ").lower()

    if len(guess) != 1 or not guess.isalpha():
        print("请输入单个字母！")
        continue

    new_hint = ""
    correct_guess = False
    for i in range(len(secret_word)):
        if secret_word[i] == guess:
            new_hint += guess
            correct_guess = True
        else:
            new_hint += hint[i]
    hint = new_hint

    if correct_guess:
        print("猜对了！")
    else:
        print("猜错了！")

    if "_" not in hint:
        print(f"恭喜！你猜中了单词: {secret_word}")
        break
else:
    print(f"游戏结束！正确答案是: {secret_word}")


def calculate(a, b, op):
    if op == "+":
        return a + b
    elif op =="-":
        return a - b
    elif op =="*":
        return a * b
    elif op =="/'":
        return a / b if b != 0 else None
    else:
        return None


print("'=== 连续计算器 ===")
print("输入格式: 数字 运算符 数字 (如: 3 + 5)")
print("输入'quit'退出")

while True:
    user_input = input("\n请输入表达式:").strip()
    if user_input.lower() == 'quit':
        break

    parts = user_input.split()
    if len(parts) !=3:
        print("格式错误!")
        continue

    try:
        num1 = float(parts[0])
        operator = parts[1]
        num2 = float(parts[2])


        result = calculate(num1, num2, operator)
        if result is None:
            print("无效运算符或除数为零!")
        else:
            print(f"结果: {result:.2f}")
    except ValueError:
        print("请输入有效数字! ")
        